Valve-gear for explosion-engines.



N. T. HARRINGTON. I VALVE GEAR FOR EXPLOSION ENGINES.

APPLICATION FILED JAN. 20,1908.

951,910w Patented Mar. 15,1910.

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N. T. HARRINGTON.

VALVE GEAR FOB. EXPLOSION ENGINES.

APPLICATION FILED IAILZO, 1908.

Patented Mar. 15,1910.

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w ifnesses I W WW M m N a b H w a m w T UITE NORMAN T. HARRINGTON, OFLANSING, MICHIGAN.

VALVE-GEAR FOR EXPLOSION-ENGINES.

Application filed January 20, 1908.

To all whom it may concern:

Be it known that I, NORMAN T. HARRING- TON, a citizen of the UnitedStates of America, residing at Lansing, in the county of Ingham andState of Michigan, have invented certain new and useful Improvements inValve-Gear for Explosion-Engines, of which the following is aspecification, reference being had therein to the accompanying drawings.

It is the object of the invention to obtain a simple construction ofvalve operating mechanism adapted for controlling and properly timingthe operation of the valves of an explosion engine of the four cycletype and avoiding the use of cams.

To this end the invention consists in the peculiar construction andorganization of a system of pivotally connected levers as hereinafterset forth.

In the drawingsFigure 1 is a side elevation of an engine to which oneform of my improved valve operating mechanism is applied; Figs. 2 and 3are diagrammatic views illustrating modified forms of the construction;and Fig. a is a diagram illustrating the operation of the mechanismshown in Fig. 1.

The operation of a valve actuating mechanism for an explosion engine ofthe four cycle type is complicated by reason of the fact that the valvesmust both remain closed during one portion of the c cle (the greaterpart of compression stro (e) while during the remaining portions of thecycle they are in operation. Thus a gearing such as might be employedfor operating the valves of a steam engine cannot be used to producethis peculiar timing effect. On the other hand, there are manyobjections to the use of cams which are ordinarily employed forproducing the proper timed operation of the valves.

My improved construction is based on the principle that any point in thelength of a pitman, which is connected at one end to a rotating crankand at its opposite end, or at some point in its length, is guided toreciprocate in a fixed path, will trace a loop, the width of which isgreater at one end than at the other. If the tracing point is located atone side of the axis of the pitman or in various other relations theretoa double loop or eight-shaped figure will be traced, and by properlyselecting the point the relative sizes and positions of the two portionsof Specification of Letters Patent,

Patented Mar. 15, 1910. Serial No. 411,736.

the loop may be variously modified. In my improved valve gearing I makeuse of this principle to translate the continuous rotary movement of thecrank into an intermittent reciprocatory movement of the valve actuatingmechanism. The interval or period of rest is not one in which thereciprocatory movement is absolutely stationary, but one in which theamount of movement is so small as to be negligible.

My invention may be embodied in several types of construction, some ofwhich are illustrated in the drawings.

As shown in Fig. 1, A is the rotary crank, which is preferably drivenfrom the main crank shaft B of the engine through the medium of a 2 to 1gearing C, so as to make one complete rotation for each cycle of theengine.

D is the rod or pitman, one end of which is connected to the crank, andE is a swinging link or rock arm connected to the opposite end of thepitman, and compelling it to reciprocate through the arc of a circle.Extending at one side of the pitman is an arm F preferably integraltherewith, the free end of which is pivotally connected with a rod orlink G. The point of the pivotal connection between these two memberswill trace a double loop, the two por tions of which are ofsubstantially equal length, but which are unsymmetrical with respect tothe longitudinal axis, forming a warped eight-shaped figure. In thisfigure the portion between the points a and b closely approximates anarc, having a radius equal to the length of the rod G, and thus this rodwill be moved angularly, but not longitudinally. On the other hand,during all of the movement of the pivot c, which connects the arm F androd G, with the exception of that portion of its orbit which liesbetween the point a and b, will cause a longitudinal reciprocation ofthe rod G first on one side and then upon the other side of its neutralposition.

To actuate the valves by the mechanism just described, any suitablemeans may be employed which provides the slight lost motion required tocompensate for the deviation of the curve a b from a true arc. As shownthe link G is connected to a rocker II which changes the direction ofreciprocation and transmits it to a rod I connected to a valve actuatingrocker J, and the compound levers K K are arranged to cooperate with therocker J and actuate respectively the valve stems L and M of the inletand exhaust valves.

In Fig. 2 a modified construction is d1agrammatically illustrated inwhich the crank A which may be driven by a two-to-one gearing (notshown) is connected to a pitman D slidably engaging a stationary pivotbearing N.

O is the reciprocatory valve actuating rod, which is pivotally attachedto the pitman D, the arrangement being such that during the rotation ofthe crank the pivot of the rod 0 will be moved upon opposite sides ofthe stationary pivot N. This will cause it to trace the double loopfigure indicated in dotted lines at P, and in which the width of one ofthe loops P is so slight as to impart very little reciprocatory movementto the rod 0. With this construction the interval of delay is that inwhich the small loop P is being traced, while during movement throughthe big loop the rod is reciprocated to actuate the valves.

In Fig. 3 still another modification is illustrated, in which the crankA is pivotally connected to a member Q, this member being also pivotallyconnected to a second crank R, which is eccentric to the first crank.The result is that the center (Z of the member R will trace a doublelooped figure indicated by dotted lines in which the large loop Scontains within it a smaller loop S, the latter being of very slightwidth. It is therefore only necessary to revolubly connect the member Q.to the valve actuating rod T, as by means of the encircling strap T, inorder to communicate a properly timed reciprocation to the valveactuating member.

lVith each modification described, a positively connected system oflevers is employed to translate the continuous rotary movement of thecrank into intermittent reciprocatory movement of the valve actuatingmember. Furthermore in each the interval of delay is effected during themovement of the pivot through some portion of the double looped orbit.

hat I claim as my invention is:

1. A valve-actuating mechanism for plosion engines of the four-cycletype, comprising a continuously rotating crank, a reciprocatoryvalveactuating member having a period in its neutral position when it issubstantially at rest, valves operated respectively by said member whileupon opposite sides of its neutral position, and a plurality ofpositively connected members connecting said crank with thevalve-actuating member and constructed to translate the movement of saidcrank into substantially intermittent movement of said valve-actuatingmember.

2. A valve-actuating mechanism for explosion engines of the four-cycletype, comprising a continuously rotating crank, a reciprocatingvalve-actuating member, inlet and exhaust valves operated respectivelyby said member while upon opposite sides of its neutral position, and aplurality of positively connected members connecting said crank with thevalve-actuating member and constructed to translate the movement of saidcrank into reciprocatory movement of said valveactuating member with aperiod including a portion of each of the compres sion and explosionstrokes of the engine in which said valve-actuating member issubstantially stationary.

3. A valve actuating mechanism for explosion engines of the four-cycletype, comprising a continuously rotating crank, a member pivotallyconnected to said crank, means determining the movement of said memberwhereby a point thereof will traverse a double looped orbit, areciprocatory valve actuating member having a connection with said crankactuated member concentric to said point, whereby the movement of saidcrank is translated into reciprocatory movement of said valve actuatingmember, with a period including a portion of each of the compression andexplosion strokes of the engine in which said valve actuating member issubstantially at rest, and inlet and exhaust valves operatedrespectively by said lastmentioned member while upon opposite sides ofits neutral position.

4:. A valve actuating mechanism for explosion engines of the tour-cycletype, comprising a continuously rotating crank, a member connected toand actuated by said crank, means for determining the movementof saidmember to cause a point therein to traverse an arc and other portionsextending upon opposite sides of said are portion, a reciprocatory valveactuating member, and a rod pivotally connected to said crank actuatingmember concentric with said point therein, the opposite end of said rodbeing connected to said valve actuating member at a point approximatingthe center of said are during the tracing thereof by said point, wherebythe movement of said crank is translated into reciprocatory movement ofsaid valve actuating member with a period including a portion of each ofthe compression and explosion strokes of the engine in which said valveactuating mechanism is substantially at rest, and inlet and exhaustvalves operated respectively by said last-mentioned member while uponopposite sides of its neutral position.

5. A valve actuating mechanism comprising a continuously rotating crank,a bellcrank lever having one arm pivotally connected to said crank,means engaging the fulcrum of said lever for determining themovementthereof in a fixed line, a reciprocatory valve actuating memberand a radius arm or link connecting said valve actuating member with theopposite arm of said bellcrank lever.

6. A valve operating mechanism comprising a continuously rotating crank,a bellcrank lever having one arm connected with said crank, a swingingfulcrumed link for said bell-crank lever, a reciprocatory valveactuating rod and a radius arm or link for connecting the opposite endof said bellcrank lever with sald reciprocating rod.

7. A valve operating mechanism comprising a continuously rotating crank,a bellcrank lever having one arm attached to said crank, a swinging linkto which said bellcrank lever is fulcrumed, a reciprocatory valveactuating rod, a radius arm or link connected to the opposite end ofsaid bellcrank lever, and a rocker connection between said radius armand'valve actuating rod.

8. A valve operating mechanism for explosion engines of the four-cycletype comprising a member rockable in opposite directions from a neutralposition to actuate the inlet and exhaust valves respectively, a

continuously rotating crank, a member connected to and actuated by saidcrank, means for determining the movement of said member to cause apoint thereof to traverse a double loop-shaped orbit, a radius armconnected to said member concentric with said point and a rod connectingsaid radius arm with said rockable valve actuating member.

In testimony whereof I affix my signature in presence of two witnesses.

NORMAN T. HARRINGTON.

Witnesses:

NELLIE KINsELLA, JAMES P. BARRY.

